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Biomedical subjects

Michael A Mont

Publications and source records attributed to Michael A Mont.

At least 37 records · Page 2Linked to original sources
PubMed2006

Pulsed electrical stimulation in patients with osteoarthritis of the knee: follow up in 288 patients who had failed non-operative therapy.

BACKGROUND: Optimized pulsed electrical stimulation (PES) regulates chondrocyte genes, enhances production of cartilage matrix materials, and inhibits production of matrix catabolic factors. METHODS: This prospective, cohort study examined the use of a PES device in treatment of knee osteoarthritis (OA) in patients who had failed non-operative therapy. Primary outcome measures were patient and physician global evaluation, and patient assessment of knee pain. RESULTS: This study included 288 (95 men, 193 women) patients who used the device from 16 to more than 600 days (mean: 889 hours). Improvement in all efficacy variables (p < 0.001) occurred. A dose-response relationship between effect size and hours of usage was observed as cumulative time increased to more than 750 hours. Improvement in patient or physician global occurred in 59.0% of patients who used it less than 750 hours, and for 73.0% of those who used it more than 750 hours. An economic analysis of a sub-group of patients showed that 45.3% reduced nonsteroidal anti-inflammatory drug (NSAID) use by 50.0% or more. CONCLUSIONS: A highly optimized PES device successfully attenuated knee OA symptoms in patients who had failed non-surgical therapy. Less than 250 hours of therapy provided relief, but improvement increased in a dose-response manner after 750 hours of cumulative use.

Adult↗
PubMed2006

Blood management in total joint arthroplasty.

Blood loss associated with total joint arthroplasty can be substantial. Various techniques for dealing with such blood loss include allogeneic blood programs, preadmission donation programs, pharmacologic agents, hemodilution, and perioperative blood salvage. This article reviews these techniques as well as the consequences of perioperative anemia. Problems associated with blood transfusions are also outlined.

Arthroplasty, Replacement↗
PubMed2005

Failure to resurface the patella during total knee arthroplasty may result in more knee pain and secondary surgery.

UNLABELLED: Resurfacing the patella during primary total knee arthroplasty is controversial. The objective of this meta-analysis was to evaluate the outcome of total knee arthroplasty with or without resurfacing of the patella with particular attention to patient satisfaction, incidence of anterior knee pain, patellar complications, and the need for secondary operations. Computerized databases were searched for citations and published randomized clinical trials relevant to patellar resurfacing from 1966-2003. Of 158 citations identified as related to patellar resurfacing during total knee arthroplasty, 14 articles met all inclusion criteria for this study. The incidence of anterior knee pain was greater in knees with nonresurfaced patellas. Secondary resurfacings for anterior knee pain was needed in 8.7% of nonresurfaced knees. No difference in reported complications existed. Total knee arthroplasty resulted in improvement of functional outcome regardless of whether the patella was resurfaced. Based on the results of this meta-analysis, nonresurfacing of the patella during primary total knee arthroplasty is likely to result in a greater incidence of anterior knee pain, the need for secondary resurfacing in almost one in 10 patients, and possibly less patient satisfaction. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗
PubMed2005

Resurfacing hip arthroplasty: comparison of a minimally invasive versus standard approach.

UNLABELLED: Metal-on-metal total hip resurfacing recently has gained popularity as a femoral-bone-preserving procedure. There has been a concomitant upsurge in demand by patients and the surgical community for the use of minimally invasive techniques for hip arthroplasty procedures. The fundamental questions are whether these techniques can lead to better short-term outcomes without leading to increased operative times, blood loss, transfusion requirements, length of stay, and clinical and/or radiographic complications. We compared a group of 25 patients (25 hips) in whom resurfacing with a minimally invasive approach was done, with a cohort of 25 patients (25 hips) who had resurfacing using a standard procedure. Patients were followed up for a mean of 19 months (range, 17-22 months). The minimally invasive group had less intraoperative blood loss (566 mL in the minimally invasive group versus 683 mL), and better 3-month Harris hip scores (78 versus 70 points). At latest followup, there were no differences in clinical (mean Harris hip scores 95 and 93 points, respectively) or radiographic outcomes. This minimally invasive approach may be a reasonable option for joint resurfacing. LEVEL OF EVIDENCE: Prognostic study, Level II (retrospective comparison study). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2005

Use of constrained acetabular liners in total hip arthroplasty.

The use of constrained acetabular liners is indicated when soft-tissue tensioning techniques such as femoral neck lengthening, component repositioning, and use of lateralized acetabular liner are ineffective. It is most commonly used as a salvage procedure in revision situations. However, a locking acetabular insert may be used for primary THAs in patients with joint or soft-tissue laxity, neuromuscular disease, or intraoperative instability. In addition to the described commercially available liners, several manufacturers will provide customized components on request.

Acetabulum↗
PubMed2005

The appropriate use of patellofemoral arthroplasty: an analysis of reported indications, contraindications, and failures.

UNLABELLED: Patellofemoral arthroplasty is going through a recent resurgence in interest with various new designs being introduced for general orthopaedic use. With this renewed enthusiasm for the procedure, it is important to understand the various indications and contraindications for using patellofemoral arthroplasty devices with the expectation that proper patient selection will improve outcome. Our purpose was to analyze the appropriate usage of these prostheses based on published historical results. A literature search was done to review the indications, contraindications, and factors contributing to the failure of these devices. We analyzed 12 studies reporting results of patellofemoral arthroplasty between 1979 and 2005. Commonly cited contraindications for using these devices have been tibiofemoral arthritis, uncorrected patellofemoral or tibiofemoral malalignment, and inflammatory arthritis. The highest failure rates were in patients with progression of osteoarthritis in other compartments or persistence of congenital or surgically uncorrected malalignment. In analyzing the reasons for failures in these reports together with issues already known to affect total knee arthroplasty surgery, we suggest an expanded list of outcome-altering factors to consider when choosing to do a patellofemoral arthroplasty. Finally, based on these observations and our own experience, suggestions on the best approach to the patient with patellofemoral arthritis are made to avoid less than optimal results if patellofemoral arthroplasty is considered. LEVEL OF EVIDENCE: Prognostic Study, Level II-3 (systematic review of Level-II studies. See the Guidelines for Authors for a complete description of levels of evidence.

Arthroplasty, Replacement, Knee↗
PubMed2005

Reductions in blood loss with use of a bipolar sealer for hemostasis in primary total knee arthroplasty.

Fifty primary total knee arthroplasties were performed in a prospective, randomized study comparing the use of a bipolar sealer device versus conventional electrocautery as the method of hemostasis. Both cohorts were evaluated for intraoperative blood loss, transfusion rate, postoperative drainage, hemoglobin levels, and Knee Society scores. A significant reduction in postoperative and total blood loss was found (p = 0.05 and p = 0.02, respectively), as well as an absence of tissue charring and smoke production in the bipolar sealer group. No difference in knee scores was found between both cohorts. These results suggest that use of this bipolar sealing device is at least as effective as standard cautery devices and can reduce blood loss, tissue damage, and smoke production in total knee arthroplasties without affecting the results.

Adult↗
PubMed2004

Total knee arthroplasty in obese patients: a comparison with a matched control group.

Thirty knees in 27 obese patients were matched to 30 knees in 27 nonobese patients, with both cohorts followed for a mean of approximately 15 years. Nine of 30 obese knees were revised, whereas 3 of 30 nonobese knees were revised, with Knee Society objective scores being higher in the nonobese group. There were more polyethylene insert revisions in the nonobese group, which may have been accounted for by a trend of higher activity levels in this group. The authors concluded that at long-term follow-up, although not statistically significant, there was a trend for obesity to influence the rate of aseptic loosening. This may occur because of increasing stress at the bone-prosthesis interface, whereas increased activity levels in the nonobese patients may adversely affect the longevity of the polyethylene insert.

Adult↗
PubMed2004

Cementless bipolar hemiarthroplasty for displaced femoral neck fractures in the elderly.

Controversy exists regarding the use of cementless femoral fixation for hip arthroplasties in elderly patients. This study reviews the clinical and radiographic outcomes of cementless bipolar hemiarthroplasties in patients older than 65 years of age. From 1998 to 2000, 256 cementless bipolar hemiarthroplasties were performed in 248 patients with displaced femoral neck fractures who had a mean age of 77 years. The mean final follow-up was 3.5 years and Harris hip scores averaged 82 points. Two loose femoral stems were revised and the rest of the implants were radiographically stable and demonstrated evidence of bone ingrowth. Six patients had debilitating groin pain necessitating conversion to total hip arthroplasty. Cementless bipolar hemiarthroplasty can be safely performed in elderly patients and can provide predictable clinical and radiographic results.

Aged↗
PubMed2004

Minimally invasive total knee arthroplasty: a 10-feature evolutionary approach.

There should not be a revolution to MIS-TKA but rather an evolutionary approach. This includes progressively downsizing incisions and causing less damage to the quadriceps mechanism. Previously,there was an extensive open exposure prolonged patella eversion and dislocation of the tibio-femoral joint. This should be evolved into a VMO muscle split with patella subluxation, retraction but not dislocation, and no gross dislocation of the tibio-femoral joint. Although the present MIS-TKA technique can be difficult and time-consuming, the resulting patient benefits should outweigh the extra effort required. In the future, we may use bone cuts and implantation with computer navigation. Each advance, however, will require new techniques, instrumentation, implants, and careful clinical studies. Caution should be taken by surgeons to avoid revolutionary approaches with existing implants, because they harbor a risk of catastrophic failure.

Arthroplasty, Replacement, Knee↗
PubMed2004

Risk factors for pulmonary emboli after total hip or knee arthroplasty.

Because it is difficult to predict which patients may sustain a pulmonary embolism after total hip or knee arthroplasty, we assessed multiple thrombophilic and hypofibrinolytic parameters to identify risk factors. Twenty-nine patients who survived a known pulmonary embolism after total knee or total hip arthroplasty were matched by age, gender, race, arthritic diagnosis, procedure, and surgery date with 29 patient-controls who had a total hip or knee arthroplasty but who did not have a symptomatic known pulmonary embolism or deep vein thrombosis. Twenty-one serologic measures and five genes associated with thrombophilia, hypofibrinolysis, or both were assessed without knowledge of group assignment. All patients with pulmonary embolism had at least one abnormality of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol versus 13 of 27 (48%) control patients. Forty-seven percent of patients who experienced pulmonary embolism had at least two abnormalities of plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, or total cholesterol, versus 7% of control patients. Preoperatively, to identify patients at high risk of pulmonary embolism, plasminogen activator inhibitor activity, dilute Russell's viper venom time, prothrombin time, and cholesterol levels were most predictive. Using at least one abnormality of these four measures as a screening test to detect risk of pulmonary embolism, the test is sensitive (100%), and the predictive value of a negative test is high (100%). After additional prospective study, this may allow identification of patients at low risk (the majority of patients) in whom anticoagulation may not be required and a small group of patients at high risk for pulmonary embolism in whom prophylactic anticoagulation should be provided.

Age Distribution↗
PubMed2004

The incorporation of morselized bone grafts in cementless acetabular revisions.

The treatment of large osteolytic lesions is a challenge during acetabular revisions. Periprosthetic bone loss can compromise the stability of new implants. The purpose of this study was to evaluate the 5- to 10-year clinical and radiographic results of morselized bone grafting for acetabular osteolysis during cementless acetabular revisions. Ninety-nine patients (108 hips) who had an acetabular revision hip arthroplasty for osteolysis were retrospectively reviewed. There were 44 men and 55 women who had a mean age of 66 years. At the index revision, the acetabular defects were debrided of granulomatous tissue and packed tightly with morselized cancellous femoral head allograft. All the revision acetabular components were implanted using cementless fixation. At a mean followup of 85 months (range, 60-118 months), the results of 103 of 108 hips (95%) were clinically and radiographically successful. The mean preoperative Harris hip score was 37 points, which improved to a mean of 91 points at the last followup. All cavitary defects had complete radiographic incorporation of the bone grafts except for two lesions. The results of this study indicate that morselized bone graft incorporates into cementless acetabular revisions. This treatment method provided a stable reconstruction in 98% of patients at a mean of 7 years followup.

Acetabulum↗
PubMed2004

Core decompression of the femoral head for osteonecrosis using percutaneous multiple small-diameter drilling.

Osteonecrosis is a disease with a wide ranging etiology and poorly understood pathogenesis seen commonly in young patients. Core decompression has historically been used in patients with small-sized or medium-sized precollapse lesions in an attempt to forestall disease progression. Typically, an 8-10 mm wide cannula trephine is used to do this procedure. The authors report on a new technique using multiple small drillings with a 3-mm Steinman pin to effectuate the core decompression. In this report, there were 32 of 45 hips (71%; 35 patients) with a successful clinical result at a mean followup of 2 years (range, 20-39 months). Twenty four of 30 Stage I hips (80%; 23 patients) had successful outcomes compared with 8 of 15 Stage II hips (57%; 12 patients) with no surgical complications occurring with this technique. This procedure is technically straightforward and led to minimal morbidity with no surgical complications. It may be effective in delaying the need for total hip arthroplasty in young patients with early (precollapse) stages of femoral head osteonecrosis.

Adolescent↗
PubMed2004

Arthrodesis of the knee.

The most common indication for arthrodesis of the knee is an infection at the site of a total knee arthroplasty. Deficiencies in bone stock and poor bone apposition adversely affect the success of a knee arthrodesis. Arthrodesis of the knee can provide a stable, painless extremity for high-functioning patients who are able to walk. Patient function after arthrodesis of the knee is superior to that after above-the-knee amputation. Conversion of a solid knee fusion to a total knee arthroplasty has a substantial complication rate.

Adolescent↗
PubMed2004

The outcome of total knee arthroplasty in obese patients.

BACKGROUND: Evidence linking increased body weight to osteoarthritis of the knee and the high prevalence of obesity underscore the importance of defining the outcome of total knee arthroplasty in obese patients. The purpose of this study was to compare the clinical and radiographic results of total knee arthroplasties performed in obese patients with those of total knee arthroplasties performed in nonobese patients. METHODS: Clinical and radiographic data on seventy-eight total knee arthroplasties in sixty-eight obese patients were compared with data on a matched group of nonobese patients. The analysis was also performed after stratification of the obese group for the degree of obesity. All patients had the same prosthesis. The clinical data that were analyzed included the Knee Society objective and functional scores, patellofemoral symptoms, activity level, and complications. RESULTS: The percentage of knees with a Knee Society score of > or =80 points at an average of eighty months was 88% in the obese group, which was significantly lower than the 99% rate in the nonobese group at the same time. The morbidly obese subgroup had a significantly higher revision rate than did the nonobese group (p = 0.02). CONCLUSIONS: The results of the present study suggest that any degree of obesity, defined as a body mass index of > or =30, has a negative effect on the outcome of total knee replacement.

Adult↗
PubMed2004

Minimally invasive total knee arthroplasty.

Currently, minimally invasive total knee arthroplasty is defined as an incision length of < 14 cm. However, the length of the incision is not the primary influence on potential postoperative benefits to the patient and should not be the only characteristic of the minimally invasive approach for knee arthroplasty. Some other factors that should also be included in this definition are: 1. The amount of soft-tissue dissection (including muscle, ligament, and capsular damage). 2. Patellar retraction or eversion. 3. Tibiofemoral dislocation. Minimally invasive surgery should not be considered to be a cosmetic procedure but rather one that addresses patients' concerns with regard to postoperative pain and slow rehabilitation. Standard total knee arthroplasties provide pain relief, but returning to activities of daily living remains a challenge for some individuals, who may take several weeks to recover. Several studies have demonstrated long-term success (at more than ten years) of standard total knee arthroplasties. However, many patients remain unsatisfied with the results of the surgery. In a study of functional limitations of patients with a Knee Society score of > or = 90 points after total knee arthroplasty, only 35% of patients stated that they had no limitations. This finding was highlighted in a study by Dickstein et al., in which one-third of the elderly patients who underwent knee replacement were unhappy with the outcome at six and twelve months postoperatively. Although many surgeons utilize objective functional scoring systems to evaluate outcome, it is likely that the criteria for a successful result of total knee arthroplasty differ between the patient and the surgeon. This was evident in a report by Bullens et al., who concluded that surgeons are more satisfied with the results of total knee arthroplasty than are their patients. Trousdale et al. showed that, in addition to concerns about long-term functional outcome, patients' major concerns were postoperative pain and the time required for recovery. Patients undergoing total knee arthroplasty have specific functional goals, such as climbing stairs, squatting, kneeling, and returning to some level of low-impact sports after surgery. Our clinical investigations demonstrated that the minimally invasive surgical approach reduces hospital stays, decreases postoperative pain, and decreases rehabilitation needs as well as enables patients to return to normal function more quickly. It is important for surgeons to take an evolutionary, rather than a revolutionary, approach when performing minimally invasive total knee arthroplasty. The surgeon should downsize incisions progressively to prevent severe damage to the quadriceps mechanism. Extensive open exposure, prolonged patellar eversion, and dislocation of the tibiofemoral joint should evolve into a vastus medialis muscle split with patellar subluxation, retraction but not dislocation of the patella, and avoidance of gross dislocation of the tibiofemoral joint. Developing the techniques of minimally invasive total knee arthroplasty may be difficult and time-consuming, but patient benefits and satisfaction should outweigh the extra effort required. These changes require well-designed clinical studies to further document their effectiveness.

Arthroplasty, Replacement, Knee↗
PubMed2004

Current overview of neurovascular structures in hip arthroplasty: anatomy, preoperative evaluation, approaches, and operative techniques to avoid complications.

Total hip arthroplasty is a common and relatively safe procedure with consistently good results. Despite its popularity and excellent results, THA is a major operation with several major neurovascular structures within reach of retractors, scalpel blades, drills, screws, and reamers. A thorough knowledge of their anatomic location and proximity to the operative field, along with a basic understanding of the principles of vascular surgery can help avoid potentially devastating consequences. Specifically, the surgeon should avoid placement of screws in the anterior-superior quadrant, be vigilant when placing retractors, and avoid excessive tension on the sciatic nerve.

Arthroplasty, Replacement, Hip↗